1. Field of the Invention
The present invention relates generally to a sealing device for use in providing a protective seal over a switch already mounted upon a panel and pertains, more specifically, to a switch boot construction which accommodates various switch installations already existing in the field while promoting longevity of the switch boot itself.
2. Description of Related Art
It has become commonplace to employ sealing devices for installed switches where it is desired to provide for protection against environmental hazards in the vicinity of a switch. In particular, switch boots have been made available for ready fitting over panel-mounted toggle switches without disturbing the existing mounting arrangement of the switches, especially where a toggle switch is mounted to a panel utilizing a front panel mounting nut, and the sealing boot is installed over the switch while maintaining the existing front panel nut in place in the original mounting position.
In order to establish a proper seal in such an installation, the switch boot usually includes a sealing structure located along a basal portion of the switch boot for being placed in sealing engagement with the front panel upon fitting the switch boot over an existing panel-mounted switch. These front-panel mounted switches ordinarily include a threaded bushing which extends axially through the front panel and projects from the face of the front panel along an axial distance which can vary from installation to installation, usually due to differences in the thickness of the front panel and the length of the threaded bushing, thus giving rise to a requirement for accommodating the variations in axial projection encountered in the field, without compromising the effectiveness of the seal provided by the switch boot, or the integrity of the switch boot itself. Although the resilient nature of the materials employed in the construction of conventional switch boots enables some compensation for variations in the axial projection of a threaded bushing by stretching of the resilient material of the switch boot in response to engagement of the resilient material of the switch boot with the threaded bushing, such engagement can induce excessive stresses in the switch boot material, tending to rupture the switch boot, as well as undue galling and wearing away of the material of the switch boot along surfaces contacted by the threaded bushing, all of which contribute to premature failure of the switch boot.